Solid state thin film batteries and other thin film devices often require shadow masking to define the various layers of the battery construction. Typical planar device construction relies on rigid substrate and mask materials and hard edge alignment procedures to register the substrate and mask together. The advent of flexible solid state thin film battery technology and the resultant use of thinner substrate and mask materials, both typically in the form of foils or strips, brings the challenge of constraining these flexible materials. Additionally, the challenge of accurately defining the associated thin film coating area during an application of a typical thin film deposition technique, such as physical vapor deposition or chemical vapor deposition arises. The legacy approach, as shown in FIG. 1, is to place a battery substrate 110 into a pocket in a metal plate 115, install a thick rigid mask framework 105 and then constrain this assembly with a clamping mechanism 120. The legacy approach suffers from many issues. For example, the thick rigid masks tend to warp with use and no longer lay flat regardless of the clamping pressure used. Typical vacuum deposition coatings tend to bleed beneath the mask edge thus creating a poorly defined thin film layer edge. Attempts to marry the thin flexible substrates with the legacy equipment suffer because thin flexible substrates and masks rarely lay flat and smooth on a planar surface and thus do not smoothly align against the edges of a defined pocket. This placement error results in a poorly location-registered coating on the surface of the substrate. A poorly location-registered or poorly edge-defined battery layer tends to produce improper battery layer interactions, in these multi-layer battery constructions, with resultant battery failure. The same shortcomings hold true for other thin film devices that typically consist of more than one thin film layer, such as thin film capacitors or transistors.